The development of solid block cleaning compositions has revolutionized the manner in which detergent compositions are dispensed by commercial and institutional entities that routinely use large quantities of cleaning materials. Solid block compositions offer unique advantages over the conventional liquids, granules or pelletized forms of detergents, including improved handling, enhanced safety, elimination of component segregation during transportation and storage, and increased concentrations of active components within the composition. Because of these benefits, solid block cleaning compositions, such as those disclosed and herein incorporated by reference in U.S. Pat. Nos. RE 32,763, RE 32,818, 4,680,134 and 4,595,520, have quickly replaced the conventional composition forms in commercial and institutional markets.
Various hardening mechanisms have been used in cleaning and sanitizing compositions for converting a fluid composition to a solid mass for containment and modification of the solubility of the active ingredients during use. For example, the active ingredients may be combined with the hardening agent under melting temperatures, commonly referred to as a “molten process,” to achieve a homogeneous mixture, and the melt then poured into a mold and cooled to a solid form. Solid alkaline detergent compositions may also be prepared from an aqueous emulsion of detergent ingredients combined with a hardening agent that can hydrate to bind free water in the emulsion which, optionally after heating and cooling, hardens to a solid.
Conventional surfactants in many detergents useful for hard surface cleaning compositions, particularly those intended for institutional and commercial use, generally contain alkyl phenol ethoxylates (APEs). APEs are effective at removing soils containing grease from a variety of surfaces and are thus effective cleansers and degreasers. Commonly used APEs include nonylphenol ethoxylates (NPE) surfactants.
While effective, APEs are disfavored due to environmental concerns. For example, NPEs are formed through the combination of ethylene oxide with nonylphenol (NP). Both NP and NPEs exhibit estrogen-like properties and may contaminate water, vegetation and marine life. NPE is also not readily biodegradable and remains in the environment or food chain for indefinite time periods. There is therefore a need in the art for an environmentally friendly and biodegradable alternative that can replace APEs in hard surface cleaners.
In general, ionic liquids refer to a class of materials including molten salts which remain liquid at temperatures of 100° C. or below. The ionic liquids are described as having to discernible melting point (based on DSC analysis) and are “flowable” at temperatures of about 100° C. or below. Ionic liquids have very low vapor pressure and generate virtually no hazardous vapors. As a result of the charged species comprising the ionic fluids, they provide a highly polar medium. Ionic liquids are generally appreciated to be environmental-friendly or “green” alternatives to conventional organic solvents.
Accordingly, it is an objective of the claimed invention to develop solid cleaning compositions incorporating ionic liquids as a means for APE-replacement and a solidification mechanism.
A further object of the invention is to develop solid formulations at room temperature incorporating ionic liquids.